Polyurethane-based binder dispersion

ABSTRACT

An inkjet ink composition comprising a polyurethane-based binder dispersion is described. The polyurethane-based binder dispersion comprises: a polyurethane, which comprises: (A) a polyisocyanate; (B) a first polyol having a chain with two hydroxyl functional groups at one end of the chain and no hydroxyl groups at an opposed end of the chain; (C) a second polyol having a chain with two hydroxyl functional groups at both ends of the chain; (D) a carboxylic acid functional group with two hydroxyl functional groups; and (E) a compound shown in formula (1): m(M+)n(X)—R—Y— (1), wherein m is 0 or 1, M is a metal, n is 2 to 10, X is an amino group, R is a C1 to C18 alkyl group, a C6 to C30 aromatic compound or a C4 to C20 aliphatic cyclic compound, and Y is SO3- or SO3H, with the proviso that when m is 0, Y is SO3H and when m is 1, Y is SO3-.

BACKGROUND

Inkjet printing is a common printing technique for recording images on avariety of media, including plain paper and photo paper. Inkjet printersform ink droplets using heat or mechanical vibration. As an example,thermal inkjet printers include resistors that create heat, whichvaporizes ink in an ink nozzle on a cartridge to create a bubble. As thebubble expands, some of the ink is pushed out of the ink nozzle and ontothe desired medium. The ink used may include a colorant and somecombination of ingredients to achieve desired print quality and/orprinter performance.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a bar graph of polyurethane dispersions versus the averageof the sum of defective nozzles.

DETAILED DESCRIPTION

Most polymers used in inkjet compositions contribute to poor SustainedPrinting and Recovery (SPAR) performance for the inks. These polymershave included polyurethanes and latexes. Without wishing to be bound bytheory, it is believed that the main reason for poor SPAR performance isthat these polymers form films that are too “hard” to re-dissolve orblast away. As a result, inkjet inks containing polyurethanes or latextend not to exhibit good jetting performance because ink droplets canpuddle around nozzle plate(s) and can eventually interfere with the inkjetting process.

SPAR is defined as the reliability of an ink that is jetted continuouslyfrom the printhead for hours with no pauses or servicing and ability torecover the print head after servicing at the end of a long print run.When subjected to this long printing environment, mostpolymer-containing inks will “crust,” or form a tough, hard, irremovablefilm on the printhead nozzle plate. This hard film clogs nozzles,hinders drop ejection and trajectory, and eventually stops the ink fromjetting altogether, resulting in a “dead” printhead. Crusting occursbecause of ink puddling, evaporation and polymer film formation. First,ink “puddling” occurs on the printhead nozzle plate, which results in apool of ink sitting on the (heated) nozzle plate. Then evaporation(driven by airflow and heat from the nozzle plate) reduces the watercontent of the ink puddle, which raises ink viscosity due toconcentration of ink components. Finally, when the polymer in the inkbecomes concentrated enough (due to evaporation), it film-forms on thenozzle plate, creating a hard “crust” that cannot be re-dissolved bywater/solvents, or blasted away by subsequent nozzle firing events.

Several SPAR mitigation strategies exist for the knownpolymer-containing inkjet inks. However, these strategies havedisadvantages. One strategy is printhead servicing, which can be used towipe/clean the printhead nozzle plate, and prevent polymer films frombuilding up and crusting. However, this approach forces the printingprocess to “pause” while servicing is completed. This “servicing cycle”lowers the average print speed of the press and has a negative impact onpress productivity. Another SPAR mitigation strategy is to decrease thepolymer content of the inkjet ink. However, this approach negativelyimpacts the inkjet ink composition durability and results ineasily-damaged printed images that tend not to survive the hotcorrugation process or other stresses in certain applications (e.g.,packaging market).

The above mitigation strategies severely limit the productivity,efficiency, and durability of prints. There is, therefore, a need forinkjet inks containing polymers that can jet better without formingexcessive puddling around nozzle plate or form “softer” films to solvethe SPAR problem. Forming “softer” films can not only reduce puddlingbut can also make it easier to remove any build-up by servicing. Inaddition, these inkjet inks should also have good performance in decap,kogation, image quality, durability, and mechability.

It has been found that the polyurethane-based binder dispersionsdescribed herein comprising a polyisocyanate and polyether polyolproduce excellent SPAR results in inkjet inks.

In particular, the polyurethane-based binder dispersions describedherein demonstrate several advantages over existing methods. Becausethese dispersions exhibit great SPAR performance over many hours ofprinting, they require little or no printhead servicing while printing.This enables higher print speeds and therefore higher press productivityfor packaging press owners. The ability to recover the printheads withminimal servicing reduces down time and increases press productivity,which can be important in the industrial printing market. In addition,these polyurethane-based binder dispersions can still be used at highamounts in the ink (i.e., more than the typical about 1 wt %), enablingprints with durability that can survive the hot corrugation process.

Polyurethane-Based Binder Dispersion

In some examples, a polyurethane-based binder dispersion is disclosed.The polyurethane-based binder dispersion comprises water and apolyurethane. The polyurethane is dispersed in the water. Thepolyurethane can comprise:

(A) a polyisocyanate;

(B) a first polyol having a chain with two hydroxyl functional groups atone end of the chain and no hydroxyl groups at an opposed end of thechain;

(C) a second polyol having a chain with two hydroxyl functional groupsat both ends of the chain;

(D) a carboxylic acid functional group with two hydroxyl functionalgroups;

(E) a compound shown in formula (1) belowm(M⁺) n(X)—R—Y  (1)

-   -   wherein    -   m is 0 or 1;    -   M is a metal;    -   n is 2 to 10;    -   X is an amino group,    -   R is a C₁ to C₁₈ alkyl group, a C₆ to C₃₀ aromatic compound or a        C₄ to C₂₀ aliphatic cyclic compound, and    -   Y is SO₃ ⁻ or SO₃H    -   with the proviso that when m is 0, Y is SO₃H and when m is 1, Y        is SO₃ ⁻.

(F) an optional homopolymer or copolymer of poly(ethylene glycol) havingone or two hydroxyl functional groups or one or two amino functionalgroups at one end of its chain.

In some examples, a polyurethane-based binder dispersion can comprise:water and a polyurethane. The polyurethane in these examples cancomprise: (A) a polyisocyanate, which is an isophorone diisocyanate(IPDI); (B) a first polyol having a chain with two hydroxyl functionalgroups at one end of the chain and no hydroxyl groups at an opposed endof the chain; (C) a polyether polyol having a chain with two hydroxylfunctional groups at both ends of the chain; (D) a carboxylic acidfunctional group with two hydroxyl functional groups; (E) a sulfonate orsulfonic acid functional group having two amino functional groups; and(F) an optional homopolymer or copolymer of poly(ethylene glycol) havingone or two hydroxyl functional groups or one or two amino functionalgroups at one end of its chain.

In some examples, the polyurethane can be defined as the following:

(A) is isophorone diisocyanate, which is present in the polyurethane inan amount of from about 24 wt % to about 30 wt % based on the totalweight of the polyurethane,

(B) is a copolymer of methylmethacrylate-co-ethylhexylacrylate-co-ethoxyethoxyethylacrylate with twohydroxy groups at one end, which is present in the polyurethane in anamount of from about 40 wt % to about 50 wt % based on the total weightof the polyurethane, wherein (B) the copolymer comprises about 75 wt %of methyl methacrylate, about 15 wt % of ethylhexylacrylate, and about10 wt % of ethoxyethoxyethylacrylate, each based on the total weight of(B),

(C) is polypropylene glycol with a M_(n) of 1000 g/mol, which is presentin the polyurethane in an amount of from about 12 wt % to about 18 wt %based on the total weight of the polyurethane,

(D) is dimethylolpropionic acid, which is present in the polyurethane inan amount of from about 2 wt % to about 6 wt % based on the total weightof the polyurethane, and

(E) is sodium 2-[(2-aminoethyl)amino]ethanesulphonate, which is presentin the polyurethane in an amount of from about 8 wt % to about 12 wt %based on the total weight of the polyurethane.

(A) Polyisocyanate(s)

In some examples, any suitable polyisocyanate may be used. For example,a polyisocyanate having an average of two or more isocyanate groups maybe used. In an example, the polyisocyanate may be an aliphatic,cycloaliphatic, araliphatic, or aromatic polyisocyanate, as well asproducts of their oligomers, used alone or in mixtures of two or more.In an example, the polyisocyanate is an aliphatic polyisocyanate or acycloaliphtic polyisocyanate, either of which has a reduced tendency toyellow.

Some examples of polyisocyanates include hexamethylene-1,6-diisocyanate(HDI), 2,2,4-trimethyl-hexamethylene-diisocyanate (TMDI), 1,12-dodecanediisocyanate, 2,4,4-trimethyl-hexamethylene diisocyanate,2-methyl-1,5-pentamethylene diisocyanate, isophorone diisocyanate(IPDI), dicyclohexylmethane-4,4-diisocyanate (H12MDI), and combinationsthereof.

The amount of the polyisocyanate in the polyurethane-based binderdispersion ranges from about 20 wt % to about 45 wt % of the totalweight of the polyurethane-based binder dispersion. In an example,polyisocyanate makes up from about 25 wt % to about 35 wt % of thepolyurethane binder.

(B) First Polyol(s)

The amount of component (b) (i.e., the first polyol) in thepolyurethane-based binder dispersion can range from about 10 wt % toabout 70 wt % of the total weight of the polyurethane-based binderdispersion. In an example, component (b) (i.e., the first polyol) canmake up from about 30 wt % to about 60 wt % of the polyurethane binder.

The first polyol (b) can include any product having a chain with twohydroxyl groups at one end of the chain and no hydroxyl groups at theopposed end of the chain. The first polyol has a number averagemolecular weight (M_(e)) ranging from about 500 g/mol to about 5000g/mol. Additionally, the first polyol has a glass transition temperature(T_(g)) ranging from about −20° C. to about 100° C. In an example, theglass transition temperature can range from about 0° C. to about 80° C.

The first polyol may be formed from the free radical polymerization of amonomer in the presence of a mercaptan that includes two hydroxylfunctional groups or two carboxylic functional groups.

Without wishing to be bound by theory, the first polyol may contributeto the improved decap of an inkjet ink because the hydroxyl groups atone end of the chain of the polyol can be incorporated into thepolyurethane backbone chain, while the group at the other end of thepolyol forms a pendant group or pendant chain depending on what specificpolyol is used. The first polyol may segregate in the aqueous ink, whichrenders the polyurethane binder readily dispersible (i.e., more stable)in the ink vehicle. The first polyol may also help prevent thepolyurethane from swelling.

Some examples of the monomer used to form component (b) include analkylester of acrylic acid or an alkylester of methacrylic acid, such asmethyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate,tetrahydrofuryl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl(meth)acrylate, benzyl (meth)acrylate, 2-aziridinylethyl (meth)acrylate,aminomethyl acrylate, aminoethyl acrylate, aminopropyl (meth)acrylate,amino-n-butyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate,N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, and N,N-diethylaminopropyl (meth)acrylate.

Some other examples of the monomer used to form component (b) include anacid group containing monomer, such as acrylic acid, methacrylic acid,carboxyethyl (meth)acrylate, 2-(meth)acryloyl propionic acid, crotonicacid, and itaconic acid. In another example, the monomer used to formcomponent (b) may be an acrylamide, an acrylamide derivative,methacrylamide, or a methacrylamide derivative. Some examples ofacrylamide and methacrylamide derivatives includehydroxyethylacrylamide, N,N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-isobutoxymethyl (meth)acrylamide.

Some further examples of the monomer used to form component (b) may bestyrene or a styrene derivative. Some examples of styrene derivativesinclude alpha-methyl styrene, p-aminostyrene, and 2-vinylpyridine.Additionally, the monomer used to form component (b) may beacrylonitrile, vinylidene chloride, a fluorine containing acrylate, afluorine containing methacrylate, a siloxane containing acrylate, asiloxane containing methacrylate, vinyl acetate, or N-vinylpyrrolidone.Some specific examples include 2,2,2-trifluoroethyl acrylate,1H,1H,3H-hexafluorobutyl acrylate, 1H,1H,3H-tetrafluoropropylmethacrylate, 1H,1H,5H-octafluoropentyl methacrylate,1H,1H,5H-octafluoropentyl acrylate, poly(dimethylsiloxane),methacryloxypropyl terminated polydimethylsiloxane DMS-R11 (made byGelest Chemicals), and (3-acryloxy-2-hydroxypropoxypropyl) terminatedpolydimethylsiloxane DMS-U21 (made by Gelest Chemicals). It is to beunderstood that any combination of monomers listed for component (b) maybe used.

Some examples of the mercaptan used to form component (b) include1,2-propanediol (thioglycerol), 1-mercapto-1,1-ethanediol,2-mercapto-1,3-propanediol, 2-mercapto-2-methyl-1,3-propanediol,2-mercapto-2-ethyl-1,3-propanediol, 1-mercapto-2,3-propanediol,2-mercaptoethyl-2-methyl-1,3-propanediol, and thioglycolic acid.

In some examples, component (b) is formed from a free radicalpolymerization of a monomer in the presence of a mercaptan including twohydroxyl functional groups or two carboxylic functional groups. Themonomer can be selected from methyl methacrylate, n-butyl acrylate,t-butyl methacrylate, t-butyl acrylate, 2-ethylhexyl acrylate,cyclohexyl methacrylate, benzyl methacrylate, isobornyl acrylate,ethoxyethyl acrylate, ethoxyethoxyethyl acrylate, methoxyethyl acrylate,methoxyethoxy methacrylate, hydroxyethyl (meth)acrylate,poly(ethyleneglycol) methyl ether (meth)acrylate (M_(w) about 200g/mol—about 500 g/mol), poly(ethyleneglycol) ethyl ether (meth)acrylate(M_(w) about 200 g/mol—about 500 g/mol). The mercaptan can be1,2-propanediol (thioglycerol).

In one example, component (b) may be formed by preparing a solution ofthe monomer and mercaptan in an organic solvent. When a combination oftwo monomers is used, the two monomers may be present in a ratio rangingfrom about 1:1 to about 9:1. In an example, methyl methacrylate and2-ethylhexyl acrylate can be used in a combination of 9:1 respectively.When a combination of three monomers is used, the three monomers may bepresent in a ratio ranging from about 5:4:1 to about 10:8:3. In anexample, methyl methacrylate, 2-ethylhexyl acrylate, and methacrylicacid ca be used in a combination of 7.5:2:0.5 respectively. Examples ofother suitable monomer combinations used in forming component (b) may befound in Table 2 of the Examples section.

After the solution (including the monomer and the mercaptan) isprepared, the solution can be placed in an inert environment. Forexample, a flow of nitrogen gas may be introduced through the solutionto create the inert environment. The solution may then be heated to asuitable temperature for polymerization, and the reaction may be allowedto occur for a suitable time. The time and temperature forpolymerization can depend upon the monomer(s) and mercaptan(s) used. Inan example, the polymerization temperature can be about 50° C. to about90° C., and the reaction can be allowed to occur for from about 6 hoursto about 12 hours. In another example, the polymerization temperaturecan be from about 65° C. to about 90° C.

The first polyol formed may include the mercaptan ranging from about 2wt % to about 10 wt % based on the total weight of the first polyol. Inan example, the mercaptan may make up about 5 wt % of the total weightof the first polyol.

(C) Second Polyol(s)

In some examples, the second polyol (i.e., component (c) can be presentin the polyurethane-based binder dispersion in an amount of from about 8wt % to about 25 wt % based on the total weight of thepolyurethane-based binder dispersion. In an example, component (b)(i.e., the first polyol) makes up from about 10 wt % to about 20 wt % ofthe polyurethane binder.

The second polyol(s) can have a number average molecular weight (Mn) ofabout 500 g/mol to about 3000 g/mol and have one hydroxyl group attachedat each end of the polyol. Examples of second polyols include polyesterpolyols, polyether polyols, polycarbonate polyol,polyester-polycarbonate polyol, or mixtures thereof.

In some examples, the second polyol can be poly(propyleneglycol),poly(tetrahydrofuran), poly(carbonate) polyol, or mixtures thereof.Examples of polycarbonate polyol include polycarbonate polyols fromKuraray Co. Ltd. (e.g., C-590, C-1050, C-1090, C-2050, C-2090, andC-3090) and polycarbonate diols from UBE Industries, Ltd. (e.g.,ETERNACOLL® UH-50, ETERNACOLL® UH-100, ETERNACOLL® UH-200, ETERNACOLL®PH-5-, ETERNACOLL® PH-100, ETERNACOLL® PH-200 and ETERNACOLL®UM90(1/3)).

(D) Carboxylic Acid Functional Group(s)

Component (d) can be a carboxylic acid functional group with twohydroxyl functional groups. The amount of component (d) in thepolyurethane-based binder dispersion ranges from 1 wt % to about 10 wt %based upon the total weight of the polyurethane. In an example,component (d) makes up from about 2 wt % to about 6 wt % of thepolyurethane binder.

The presence of component (d) assists in the ability of the polyurethaneto be dissolved or dispersed in water after ionization with a base. Aspreviously stated, component (d) can be a carboxylic acid. In someinstances, component (d) includes two or more hydroxyl groups. Component(d) may have a number average molecular weight (Mn) of about 500 g/mol.Examples of component (d) may be derived from hydroxy-carboxylic acidshaving the general formula (HO)xQ(COOH)y, where Q is a straight orbranched hydrocarbon radical containing 1 to 12 carbon atoms, and x is 2or 3 and y ranges from 1 to 3.

Examples of component (d) can include dimethylol propionic acid (DMPA),dimethylol butanoic acid (DMBA), alanine, citric acid, tartaric acid,glycolic acid, lactic acid, malic acid, dihydroxymaleic acid,dihydroxytartaric acid, or mixtures thereof.

(E) Sulfonic/Sulfonate Amine Compound(s)

In some examples, component (e) can be a compound shown in formula (1)belowm(M⁺) n(X)—R—Y  (1)

-   -   wherein    -   m is 0 or 1;    -   M is a metal;    -   n is 2 to 10;    -   X is an amino group,    -   R is a C₁ to C₁₈ alkyl group, a C₆ to C₃₀ aromatic compound or a        C₄ to C₂₀ aliphatic cyclic compound, and    -   Y is SO₃ ⁻ or SO₃H    -   with the proviso that when m is 0, Y is SO₃H and when m is 1, Y        is SO₃ ⁻.

In some examples, m is 1; M is sodium, potassium, magnesium, calcium, orlithium; n is 2 to 4; X is an amino group; R is a C1 to C8 alkyl group;and Y is SO₃ ⁻.

In some examples, the sulfonate or sulfonic acid amine compound (i.e.,component (e)) can have two or more amino functional groups. In someexamples, sulfonate or sulfonic acid amine compound (i.e., component(e)) can have two to ten amino functional groups. In some examples,sulfonate or sulfonic acid amine compound (i.e., component (e)) can havetwo to four amino functional groups. In some examples, sulfonate orsulfonic acid amine compound (i.e., component (e)) can have two aminofunctional groups.

The polyurethane-based binder dispersion disclosed herein, which mayinclude component (e), improves the decap performance and printreliability of the inkjet ink including the dispersion while improvingimage quality. Component (e) may be present in the polyurethane-basedbinder dispersion an amount ranging from about 1 wt % to about 20 wt %based upon the total weight of the polyurethane-based binder dispersion.In an example, component (e) can be present in an amount ranging fromabout 2 wt % to about 20 wt % of the polyurethane-based binderdispersion. In another example, component (e) may be present in anamount of about 5 wt % to about 15 wt % of the polyurethane-based binderdispersion.

Some examples of component (e) include ethyldiamineethylsulfonic acid ora salt thereof, ethyldiaminepropylsulfonic acid or a salt thereof,5-amino-2-(aminomethyl)-1-pentanesulfonic acid or a salt thereof,2,3-diamino-1-propanesulfonic acid or a salt thereof,3-[bis(2-aminoethyl)amino]-1-propanesulfonic acid or a salt thereof,2-[bis(2-aminoethyl)amino]-ethanesulfonic acid or a salt thereof,2-[(2-aminoethyl)amino]-1-propanesulfonic acid or a salt thereof,2-[[2-[(1-methylethyl)amino]ethyl]amino]-ethanesulfonic acid or a saltthereof, 2-[(2-aminoethyl)amino]-1-pentanesulfonic acid or a saltthereof, or mixtures thereof.

In some examples, component (e) is a compound shown in Table 1 below.

TABLE 1

I

II

III

IV

V

VI

VII

VIII

IX

In some examples, component (e) can be sodium2-[(2-aminoethyl)amino]ethanesulphonate or sodiumdiaminoethylpropylsulfonate.

(F) Homopolymer(s) or Copolymer(s) of Poly(Ethylene Glycol)

In some examples, component (f) can be a homopolymer or copolymer ofpoly(ethylene glycol) having one hydroxyl functional group or one aminofunctional group. In other examples, component (d) may be a homopolymeror copolymer of poly(ethylene glycol) having two hydroxyl functionalgroups or two amino functional groups at one end of its chain.

The homopolymer or copolymer of poly(ethylene glycol) has a numberaverage molecular weight (Mn) ranging from about 500 g/mol to about5,000 g/mol. In another example, the homopolymer or copolymer ofpoly(ethylene glycol) has a number average molecular weight (Mn) rangingfrom about 500 g/mol to about 3,000 g/mol. Component (f) also has awater solubility of greater than 30% v/v (volume of poly(ethyleneglycol) to volume of water).

Examples of the polyurethane-based binder dispersion disclosed hereinincluding component (f) can increase the gloss and optical density of aprinted image on media when compared to the gloss and optical density ofa printed image on the same media formed with an ink that includes othertypes of polyurethane dispersions that do not include component (f).This may be due, in part, because, when included, component (f) preventsthe polyurethane-based binder dispersion from reacting with anunderlying pre-treatment fixing fluid, which would otherwise cause thepolyurethane binder to undesirably coagulate when the ink composition isapplied to the medium. As such, component (f) renders thepolyurethane-based binder dispersion insensitive to the pre-treatmentfixing fluid, and thus prevents undesirable polyurethane coagulation. Asthe polyurethane-based binder does not strongly interact with thepre-treatment fixing fluid to cause coagulation, the polyurethane canform a film when printed, which advantageously affects the gloss andoptical density of the printed image.

The amount of component (f) in the polyurethane-based binder dispersionranges from 0 wt % to about 20 wt % based upon the total weight of thepolyurethane-based binder dispersion. In an example, component (f) canbe present in the polyurethane-based binder dispersion in an amount offrom about 5 wt % to about 10 wt % of the polyurethane-based binderdispersion.

Any copolymer of poly(ethylene glycol) with one or two hydroxyl and/oramino group(s) may be used as component (f), as long as the copolymerhas water solubility of > about 30% v/v and a suitable number averagemolecular weight. Some examples of suitable copolymers for component (f)include a copolymer of poly(ethylene) and poly(ethylene glycol) with onehydroxyl functional group

where m=1-10 and n=5-50, a copolymer of poly(propylene glycol) andpoly(ethylene glycol) with one hydroxyl functional group, and acopolymer of poly(ethylene glycol) and poly(propylene glycol) with oneamino functional group. Some commercially available examples of thecopolymer of poly(ethylene glycol) and poly(propylene glycol) with oneamino functional group include JEFFAMINE® M-1000

where x=19 and y=3) and JEFFAMINE® M-2070

where x=31 and y=10) (both produced by Huntsman Chemicals).

Some additional examples of component (f) include a poly(ethyleneglycol) homopolymer, such as monoamine terminated poly(ethylene glycol)

where n=5-100, and a poly(ethylene glycol) mono alkyl ether. Examples ofthe poly(ethylene glycol) mono alkyl ether include an alkyl group withC1 to C8 straight or branched hydrocarbons, such as methyl, ethyl, andbutyl groups. Examples of the poly(ethylene glycol) mono alkyl etherinclude poly(ethylene glycol) monomethyl ether

where n=5-100, poly(ethylene glycol) monoethyl ether, poly(ethyleneglycol) monopropyl ether, and poly(ethylene glycol) monobutyl ether.

Furthermore, any homopolymer of poly(ethylene glycol) with two hydroxylor amino groups at one end of the polymer chain may alternatively beused as component (f), as long as the homopolymer has water solubilityof > about 30% v/v and a suitable number average molecular weight. As anexample, the homopolymer may be two hydroxyl terminated poly(ethyleneglycol), where both hydroxyls are located at one end of the chain. Onecommercially available example is YMER™ N120 (a linear difunctionalpolyethylene glycol monomethyl ether from Perstorp).

Method(s) of Making the Polyurethane-Based Binder Dispersion(s)

In an example of the first step of the method for making thepolyurethane binder dispersion, components (A), (B), (C), and (D) can bemixed in a reactor with an organic solvent (e.g., methyl ethyl ketone(MEK), tetrahydrofuran (THF), ethyl acetate, acetone, or combinationsthereof) and a catalyst (e.g., dibutyl tin dilaurate, bismuth octanoate,zinc neodecanote and 1,4-diazabicyclo[2.2.2]octane). The reactor may bemaintained at a constant temperature and under a dry air mixture. Thecomponents may be mixed and the polymerization reaction may be allowedto occur until the % NCO reaches the theoretical value. In an example,the reaction time ranges from about 4 hour to about 14 hours. In anotherexample, the polymerization reaction can occur for about 10 hours atabout 60° C. to achieve the theoretical value of the % NCO.

In an example of the second step of the method for making thepolyurethane polymer, component (F) can then be added to thepolymerization reaction of components (A), (B), (C), and (D).Polymerization can be continued until the % NCO reaches the theoreticalvalue. In this step, the polymerization reaction may be allowed to occurfor a time ranging from about 1 hour to about 4 hours. In an example,the polymerization reaction can occurs for about 2 hours at about 60° C.to achieve the theoretical value of the % NCO.

In an example of the third step of the method for making thepolyurethane polymer, component (E) can be dissolved in one equivalentof a base and a sufficient amount of deionized water to fully dissolvecomponent (E). Some examples of the base include ammonia,trimethylamine, triethylamine, sodium hydroxide, potassium hydroxide,and lithium hydroxide. The polymer solution made from components (A),(B), (C), and (D) and in some instances (F) can be cooled to atemperature ranging from about 30° C. to about 50° C. The aqueoussolution of component (E) can be added to the polymer solution from thefirst step (if component (F) is not included) or the second step (ifcomponent (F) is included) with vigorous mixing at a temperature rangingfrom about 30° C. to about 50° C. for at least about 30 minutes.

In an example of the fourth step of the method for making thepolyurethane polymer comprising components (A)-(E) and optionally (F),the polyurethane solution may be added to water including a base slowly(e.g., over a 10 minute period) with vigorous agitation or vice versa.The mixture may be stirred and organic solvent may be removed bydistillation to form the polyurethane binder dispersion. In an example,the acid number of the polyurethane-based binder dispersion ranges fromabout 10 mg KOH/g solid resin to about 70 mg KOH/g solid resin or fromabout 30 mg KOH/g solid resin to less than 60 mg KOH/g solid resin.

Once the polyurethane-based binder dispersion is prepared, the particlesize of the polyurethane-based binder in the dispersion ranges fromabout 10 nm to about 200 nm. In an example, the particle size of thepolyurethane binder ranges from about 10 nm to about 100 nm.

In some examples, the polyurethane-based binder dispersion can includefrom about 10 wt % to about 95 wt % water based on the total weight ofthe polyurethane-based binder dispersion.

Inkjet Ink(s)

The inkjet ink, which includes the polyurethane-based binder dispersiondisclosed herein, may be included in a single cartridge ink set or amultiple-cartridge ink set (which may or may not include thepre-treatment fixer fluid). In the multiple-cartridge ink set, anynumber of the multiple inks may have the polyurethane binderincorporated therein.

In an example, the inkjet ink disclosed herein can include a co-solvent(in addition to any water that is present), a colorant, water (which isthe main solvent), a surfactant, and the polyurethane-based binderdispersion.

In some examples, an inkjet ink composition can comprise water; at leastone co-solvent; at least one surfactant; at least one colorant; and apolyurethane-based binder dispersion. The polyurethane-based binderdispersion can comprise: water and a polyurethane, wherein thepolyurethane can comprise:

component (A), which is isophorone diisocyanate and is present in thepolyurethane in an amount of from about 24 wt % to about 30 wt % basedon the total weight of the polyurethane,

component (B), which is a copolymer of methylmethacrylate-co-ethylhexylacrylate-co-ethoxyethoxyethylacrylate with twohydroxy groups at one end and is present in the polyurethane in anamount of from about 40 wt % to about 50 wt % based on the total weightof the polyurethane, wherein (B) the copolymer comprises about 75 wt %of methyl methacrylate, about 15 wt % of ethylhexylacrylate, and about10 wt % of ethoxyethoxyethylacrylate, each based on the total weight of(B),

component (C), which is polypropylene glycol with a M_(n) of 1000 g/moland is present in the polyurethane in an amount of from about 12 wt % toabout 18 wt % based on the total weight of the polyurethane,

component (D), which is dimethylolpropionic acid and is present in thepolyurethane in an amount of from about 2 wt % to about 6 wt % based onthe total weight of the polyurethane, and

component (E), which is sodium 2-[(2-aminoethyl)amino]ethanesulphonateand is present in the polyurethane in an amount of from about 8 wt % toabout 12 wt % based on the total weight of the polyurethane.

Colorant(s)

The colorant(s) in the inkjet ink composition(s) described herein caninclude inorganic pigments, organic pigments, dyes, and combinationsthereof.

The pigment may be any color, including, as examples, a cyan pigment, amagenta pigment, a yellow pigment, a black pigment, a violet pigment, agreen pigment, a brown pigment, an orange pigment, a purple pigment, awhite pigment, a metallic pigment (e.g., a gold pigment, a bronzepigment, a silver pigment, or a bronze pigment), a pearlescent pigment,or combinations thereof.

Examples of suitable yellow organic pigments include C.I. Pigment Yellow1, C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 4,C.I. Pigment Yellow 5, C.I. Pigment Yellow 6, C.I. Pigment Yellow 7,C.I. Pigment Yellow 10, C.I. Pigment Yellow 11, C.I. Pigment Yellow 12,C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I. Pigment Yellow 16,C.I. Pigment Yellow 17, C.I. Pigment Yellow 24, C.I. Pigment Yellow 34,C.I. Pigment Yellow 35, C.I. Pigment Yellow 37, C.I. Pigment Yellow 53,C.I. Pigment Yellow 55, C.I. Pigment Yellow 65, C.I. Pigment Yellow 73,C.I. Pigment Yellow 74, C.I. Pigment Yellow 75, C.I. Pigment Yellow 77,C.I. Pigment Yellow 81, C.I. Pigment Yellow 83, C.I. Pigment Yellow 93,C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97,C.I. Pigment Yellow 98, C.I. Pigment Yellow 99, C.I. Pigment Yellow 108,C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow113, C.I. Pigment Yellow 114, C.I. Pigment Yellow 117, C.I. PigmentYellow 120, C.I. Pigment Yellow 122, C.I. Pigment Yellow 124, C.I.Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 133,C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow147, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I. PigmentYellow 154, C.I. Pigment Yellow 167, C.I. Pigment Yellow 172, C.I.Pigment Yellow 180, and C.I. Pigment Yellow 185.

Examples of suitable blue or cyan organic pigments include C.I. PigmentBlue 1, C.I. Pigment Blue 2, C.I. Pigment Blue 3, C.I. Pigment Blue 15,Pigment Blue 15:3, C.I. Pigment Blue 15:34, C.I. Pigment Blue 15:4, C.I.Pigment Blue 16, C.I. Pigment Blue 18, C.I. Pigment Blue 22, C.I.Pigment Blue 25, C.I. Pigment Blue 60, C.I. Pigment Blue 65, C.I.Pigment Blue 66, C.I. Vat Blue 4, and C.I. Vat Blue 60.

Examples of suitable magenta, red, or violet organic pigments includeC.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. PigmentRed 4, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I.Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 10, C.I. Pigment Red11, C.I. Pigment Red 12, C.I. Pigment Red 14, C.I. Pigment Red 15, C.I.Pigment Red 16, C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. PigmentRed 19, C.I. Pigment Red 21, C.I. Pigment Red 22, C.I. Pigment Red 23,C.I. Pigment Red 30, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I.Pigment Red 37, C.I. Pigment Red 38, C.I. Pigment Red 40, C.I. PigmentRed 41, C.I. Pigment Red 42, C.I. Pigment Red 48(Ca), C.I. Pigment Red48 (Mn), C.I. Pigment Red 57 (Ca), C.I. Pigment Red 57:1, C.I. PigmentRed 88, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red122, C.I. Pigment Red 123, C.I. Pigment Red 144, C.I. Pigment Red 146,C.I. Pigment Red 149, C.I. Pigment Red 150, C.I. Pigment Red 166, C.I.Pigment Red 168, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I.Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 177, C.I.Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 184, C.I.Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 202, C.I.Pigment Red 209, C.I. Pigment Red 219, C.I. Pigment Red 224, C.I.Pigment Red 245, C.I. Pigment Red 286, C.I. Pigment Violet 19, C.I.Pigment Violet 23, C.I. Pigment Violet 32, C.I. Pigment Violet 33, C.I.Pigment Violet 36, C.I. Pigment Violet 38, C.I. Pigment Violet 43, andC.I. Pigment Violet 50.

Carbon black may be a suitable inorganic black pigment. Examples ofcarbon black pigments include those manufactured by Mitsubishi ChemicalCorporation, Japan (such as, e.g., carbon black No. 2300, No. 900,MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, and No. 2200B);various carbon black pigments of the RAVEN® series manufactured byColumbian Chemicals Company, Marietta, Ga., (such as, e.g., RAVEN® 5750,RAVEN® 5250, RAVEN® 5000, RAVEN® 3500, RAVEN® 1255, and RAVEN® 700);various carbon black pigments of the BLACK PEARLS® series, REGAL®series, the MOGUL® series, or the MONARCH® series manufactured by CabotCorporation, Boston, Mass., (such as, e.g., BLACK PEARLS® 880 CarbonBlack, REGAL® 400R, REGAL® 330R, and REGAL® 660R); and various blackpigments manufactured by Evonik Degussa Corporation, Parsippany, N.J.,(such as, e.g., Color Black FW1, Color Black FW2, Color Black FW2V,Color Black FW18, Color Black FW200, Color Black S150, Color Black S160,Color Black S170, PRINTEX® 35, PRINTEX® U, PRINTEX® V, PRINTEX® 140U,Special Black 5, Special Black 4A, and Special Black 4). An example ofan organic black pigment includes aniline black, such as C.I. PigmentBlack 1.

Some examples of green organic pigments include C.I. Pigment Green 1,C.I. Pigment Green 2, C.I. Pigment Green 4, C.I. Pigment Green 7, C.I.Pigment Green 8, C.I. Pigment Green 10, C.I. Pigment Green 36, and C.I.Pigment Green 45.

Examples of brown organic pigments include C.I. Pigment Brown 1, C.I.Pigment Brown 5, C.I. Pigment Brown 22, C.I. Pigment Brown 23, C.I.Pigment Brown 25, C.I. Pigment Brown 41, and C.I. Pigment Brown 42.

Some examples of orange organic pigments include C.I. Pigment Orange 1,C.I. Pigment Orange 2, C.I. Pigment Orange 5, C.I. Pigment Orange 7,C.I. Pigment Orange 13, C.I. Pigment Orange 15, C.I. Pigment Orange 16,C.I. Pigment Orange 17, C.I. Pigment Orange 19, C.I. Pigment Orange 24,C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 38,C.I. Pigment Orange 40, C.I. Pigment Orange 43, and C.I. Pigment Orange66.

A suitable metallic pigment includes a metal chosen from gold, silver,platinum, nickel, chromium, tin, zinc, indium, titanium, copper,aluminum, and alloys of any of these metals. These metals may be usedalone or in combination with two or more metals or metal alloys. Someexamples of metallic pigments include STANDART® R0100, STANDART® R0200,and DORADO® gold-bronze pigments (available from Eckart Effect Pigments,Wesel, Germany).

In some examples, the above pigments can be used alone or in anycombination with one another.

The total amount of the colorant(s) in the inkjet ink composition rangesfrom about 0.1 wt % to about 15 wt % based on the total weight of theinkjet ink composition. In some examples, the total amount of thecolorant(s) in the inkjet ink composition ranges from about 1 wt % toabout 8 wt % based on the total weight of the inkjet ink composition.The average particle size of these colorant(s) may range from about 80nm to about 400 nm.

Colorant(s) in a Dispersion

In the examples disclosed herein, the pigment may be dispersed by ananionic polymer (i.e., anionic polymeric dispersant). The dispersant maybe present in an amount ranging from about 0.1 wt % to about 5 wt % of atotal weight of the ink composition.

In an example, the dispersant may be styrene-acrylic-type dispersantssuch as acrylic dispersants having i) hydrophilic monomers includingacidic monomers, and ii) hydrophobic monomers. The acid number of thedispersant may range from about 120 mg/g to about 300 mg/g. It is to beunderstood that the styrene-acrylic-type dispersants are water soluble.

Acidic monomers that may be used in the acrylic dispersant may include,for example, acrylic acid, methacrylic acid, ethacrylic acid,dimethylacrylic acid, maleic anhydride, maleic acid, vinylsulfonate,cyanoacrylic acid, vinylacetic acid, allylacetic acid, ethylidineaceticacid, propylidineacetic acid, crotonoic acid, fumaric acid, itaconicacid, sorbic acid, angelic acid, cinnamic acid, styrylacrylic acid,citraconic acid, glutaconic acid, aconitic acid, phenylacrylic acid,acryloxypropionic acid, aconitic acid, phenylacrylic acid,acryloxypropionic acid, vinylbenzoic acid, N-vinylsuccinamidic acid,mesaconic acid, methacroylalanine, acryloylhydroxyglycine, sulfoethylmethacrylic acid, sulfopropyl acrylic acid, styrene sulfonic acid,sulfoethylacrylic acid, 2-methacryloyloxymethane-1-sulfonic acid,3-methacryoyloxypropane-1-sulfonic acid, 3-(vinyloxy)propane-1-sulfonicacid, ethylenesulfonic acid, vinyl sulfuric acid, 4-vinylphenyl sulfuricacid, ethylene phosphonic acid, vinyl phosphoric acid, vinyl benzoicacid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and combinationsthereof.

Examples of the hydrophobic monomers that can be polymerized in theacrylic dispersant may include styrene, p-methyl styrene, methylmethacrylate, hexyl acrylate, hexyl methacrylate, butyl acrylate, butylmethacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate,propyl methacrylate, octadecyl acrylate, octadecyl methacrylate, stearylmethacrylate, vinylbenzyl chloride, isobornyl acrylate,tetrahydrofurfuryl acrylate, 2-phenoxyethyl methacrylate, ethoxylatednonyl phenol methacrylate, isobornyl methacrylate, cyclohexylmethacrylate, t-butyl methacrylate, n-octyl methacrylate, laurylmethacrylate, trydecyl methacrylate, alkoxylated tetrahydrofurfurylacrylate, isodecyl acrylate, isobornylmethacrylate, and combinationsthereof.

Co-Solvent(s)

In some examples, the co-solvents in the inkjet ink compositions caninclude aliphatic alcohols, aromatic alcohols, triols, glycol ethers,poly(glycol) ethers, lactams, formamides, acetamides, long chainalcohols, ethylene glycol, propylene glycol, diethylene glycols,triethylene glycols, glycerine, dipropylene glycols, glycol butylethers, polyethylene glycols, polypropylene glycols, amides, ethers,carboxylic acids, esters, organosulfides, organosulfoxides, sulfones,alcohol derivatives, carbitol, butyl carbitol, cellosolve, etherderivatives, amino alcohols, and ketones. For example, co-solvents caninclude primary aliphatic alcohols of 30 carbons or less, primaryaromatic alcohols of 30 carbons or less, secondary aliphatic alcohols of30 carbons or less, secondary aromatic alcohols of 30 carbons or less,1,2-diols of 30 carbons or less, 1,3-diols of 30 carbons or less,1,5-diols of 30 carbons or less, ethylene glycol alkyl ethers, propyleneglycol alkyl ethers, poly(ethylene glycol) alkyl ethers, higher homologsof poly(ethylene glycol) alkyl ethers, poly(propylene glycol) alkylethers, higher homologs of poly(propylene glycol) alkyl ethers, lactams,substituted formamides, unsubstituted formamides, substitutedacetamides, and unsubstituted acetamides.

Specific examples of certain co-solvents that may likewise be usedinclude, but are not limited to, hydantoin glycol (such as, e.g.,1,3-bis-(2-hydroxyethyl)-5,5-dimethylhydantoin),1,(2-hydroxyethyl)-2-pyrrolidinone,1-(2-hydroxyethyl)-2-imidazolidinone, tetratethylene glycol,1,2,6-hexanetriol, glycerol, glycerol propoxylate, 1,5-pentanediol,LIPONIC® ethoxylated glycerol 1 (LEG-1), LIPONIC® ethoxylated glycerol 7(LEG-7), 2-methyl-2,4-pentanediol, 2-methyl-1,3-propanediol,2-ethyl-2-hydroxymethyl-1,3-propanediol, diethylene glycol,3-methoxybutanol, propylene glycol monobutyl ether,1,3-dimethyl-2-imidazolidinone, the like, or combinations thereof.

Co-solvents can be added to reduce the rate of evaporation of water inthe inkjet ink, to minimize clogging, or provide other improvedproperties related to viscosity, pH, surface tension, optical density,gamut, durability, decap, and print quality, for example.

The co-solvents can be present in the inkjet ink compositions in amountsranging from about 1 wt % to about 40 wt % (based on the total weight ofthe inkjet ink composition), depending, at least in part, on the jettingarchitecture.

Surfactant(s)

Surfactant(s) can be added to inkjet ink composition(s) in someexamples. The surfactants in the inkjet ink compositions may includenonionic, cationic, and/or anionic surfactants, which may be present inamounts ranging from about 0.1 wt % to about 10 wt % based on the totalweight of the inkjet ink composition. In some examples, the inkjet inkcomposition can include surfactants in amounts ranging from about 0.1 wt% to about 5 wt % based on the total weight of the inkjet inkcomposition.

In some examples, the inkjet ink compositions can include ethoxylatedalcohols such as those from the Tergitol® series (e.g., Tergitol® 15S30,or Tergitol® 15S9), manufactured by Dow Chemical; surfactants from theSurfynol® series (e.g., Surfynol® 104, Surfynol® 440 and Surfynol® 465),and Dynol™ series (e.g., Dynol™ 360, Dynol™ 604, and Dynol™ 607)manufactured by Air Products and Chemicals, Inc.; fluorinatedsurfactants, such as those from the Zonyl® family (e.g., Zonyl® FSO andZonyl® FSN surfactants), manufactured by E.I. DuPont de Nemours andCompany; alkoxylated surfactant such as Tego® Wet 510 manufactured fromEvonik; fluorinated PolyFox® nonionic surfactants (e.g., PF159 nonionicsurfactants), manufactured by Omnova; or combinations thereof.

Polysorbate surfactants can include Polysorbate 20 (or polyoxyethylene20 sorbitan monolaurate), Polysorbate 40 (or polyoxyethylene 20 sorbitanmonopalmitate), Polysorbate 60 (or polyoxyethylene 20 sorbitanmonostearate), Polysorbate 80 (or polyoxyethylene 20 sorbitanmonooleate), or the like. However, not all of these polysorbates have atleast 50 wt % lipophilic oleic acid groups and having an HLB value ofless than 15. Brand names for these polysorbate surfactants includethose sold under the tradename Tween® or Alkest®. Regarding thenomenclature of these polysorbates, the number “20” following“polyoxyethylene” refers to the total number of oxyethylene—(CH2CH2O)—groups found in the molecule. The number 20, 40, 60, or 80 following“polysorbate” is related to the type of fatty acid associated with thepolyoxyethylene sorbitan portion. Monolaurate is indicated by 20,monopalmitate is indicated by 40, monostearate by 60 and monooleate by80.

Other polysorbates can likewise be used, including Polysorbate 85, orTween® 85, which is polyethylene glycol sorbitan trioleate; orPolysorbate 81, or Tween® 81, which is a polyoxyethylene (5) sorbitanmonooleate. Tween® 85 and Tween® 81 are oleyl type compounds and include70 wt % oleic acid. Polyoxyethylene sorbitan dioleate can also be used.

Another surfactant that can be used includes polyoxyethylene glycolethers. Examples surfactants that can be used include Brij® S, Brij® O,Brij® C, and Brij® L type surfactants Synperonic surfactants can also beused. Specific examples include Brij® S10, Brij® S5, Brij®, S15, Brij®S20, Brij® S2/93, Brij® S7, Brij® 98/O20, Brij® O10, Brij® O2, Brij®,O3, Brij® O5, Brij® C2, Brij® C7, Brij® C10, Brij®, C20, Brij® L4/30,Brij® L9, Brij® L15, Synperonic® 91-2.5, Synperonic® 91-2.5, Synperonic®91-10, or mixtures thereof.

Additive(s)

The additives in the inkjet ink compositions can be selected from thegroup consisting of anti-kogation agents, pH adjusters, antimicrobialagents, sequestering agents, viscosity modifiers, humectants,penetrants, wetting agents, preservatives, jettability additives, waxes,and mixtures thereof.

Kogation refers to the deposit of dried ink on a heating element of athermal inkjet printhead. Anti-kogation agent(s) is/are included toassist in preventing the buildup of kogation. Anti-kogation agents caninclude an anionic surfactant, a nonionic surfactant, a zwitterionicsurfactant, an amphoteric surfactant, or mixtures thereof. A list ofsurfactants is given above. In some examples, the anti-kogation agentscan include oleth-3-phosphate (commercially available as CRODAFOS® O3Aor CRODAFOS® N-3 acid) or dextran 500 k. The anti-kogation agent may bepresent in the inkjet ink composition in an amount ranging from about0.1 wt % to about 3 wt % of the total weight of the inkjet inkcomposition.

pH adjuster(s) can be added to the inkjet ink compositions in someexamples. pH adjuster(s) can include sodium hydroxide, potassiumhydroxide, ammonia, hydrochloric acid, nitric acid, sulfuric acid, and(poly)alkanolamines such as triethanolamine and2-amino-2-methyl-1-propaniol, or mixtures thereof.

In some examples, the inkjet ink composition may also includeantimicrobial agent(s). Suitable antimicrobial agents include biocidesand fungicides. Examples of antimicrobial agents include ACTICIDE® M20(i.e., active ingredient is 2-methyl-4-isothiazolin-3-one), ACTICIDE®B20 (i.e., active ingredient is 1,2-benzisothiazolin-3-one), AMP (i.e.,amino-tris-(methylene phosphonate), TRIS (i.e.,tris(hydroxymethyl)nitromethane), and mixtures thereof. Other examplesof antimicrobial agent(s) include NUOSEPT® (Ashland Inc.), UCARCIDE™ orKORDEK™ (Dow Chemical Co.), and PROXEL® (Arch Chemicals) series, andcombinations thereof.

In some examples, sequestering agents can be added to the inkjet inkcompositions. These sequestering agents may be useful to impart improvedstability characteristics to the inkjet ink composition and can includean alkali metal, an alkaline earth metal, and an ammonium salt of alinear aliphatic substituted glycine compound. The term “linearaliphatic substituted glycine” designates glycine compounds in which theamino group of glycine has been substituted with linear aliphaticgroups. In some examples, the sequestering agents may include the alkalimetal (e.g., sodium), alkaline earth metal (e.g., calcium) and ammoniumsalts of ethylene diamine tetraacetic acid, nitrilo triacetic acid,diethylene triamine pentaacetic acid, hydroxyethylene diamine triaceticacid, dihydroxyethyl glycine, iminodiacetic acid and ethanol diglycine.Similar salts of other linear aliphatic substituted glycine compoundsmay also be used.

In some examples, viscosity modifiers can be added to the inkjet inkcompositions. Examples of viscosity modifiers include aliphatic ketones,stearone, 2-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol,4-nitrobenzyl alcohol, 4-hydroxy-3-methoxy benzyl alcohol,3-methoxy-4-nitrobenzyl alcohol, 2-amino-5-chlorobenzyl alcohol,2-amino-5-methylbenzyl alcohol, 3-amino-2-methylbenzyl alcohol,3-amino-4-methyl benzyl alcohol, 2 (2-(aminomethyl)phenylthio)benzylalcohol, 2,4,6-trimethylbenzyl alcohol,2-amino-2-methyl-1,3-propanediol, 2-amino-1-phenyl-1,3-propanediol,2,2-dimethyl-1-phenyl-1,3-propanediol, 2-bromo-2-nitro-1,3-propanediol,3-tert-butylamino-1,2-propanediol, 1,1-diphenyl-1,2-propanediol,1,4-dibromo-2,3-butanediol, 2,3-dibromo-1,4-butanediol,2,3-dibromo-2-butene-1,4-diol, 1,1,2-triphenyl-1,2-ethanediol,2-naphthalenemethanol, 2-methoxy-1-naphthalenemethanol, decafluorobenzhydrol, 2-methylbenzhydrol, 1-benzeneethanol, 4,4′-isopropylidenebis(2-(2,6-dibromo phenoxy)ethanol), 2,2′-(1,4-phenylenedioxy)diethanol,2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol,di(trimethylolpropane), 2-amino-3-phenyl-1-propanol,tricyclohexylmethanol, tris(hydroxymethyl)aminomethane succinate,4,4′-trimethylene bis(1-piperidine ethanol), N-methyl glucamine, ormixtures thereof.

In some examples, the inkjet ink compositions described herein maycontain a high-boiling water-soluble organic solvent, which can serve asa wetting agent or humectant for imparting water retentivity and wettingproperties to the inkjet ink composition. Such a high-boilingwater-soluble organic solvent includes one having a boiling point of180° C. or higher. Examples of the water-soluble organic solvent havinga boiling point of 180° C. or higher are ethylene glycol, propyleneglycol, diethylene glycol, pentamethylene glycol, trimethylene glycol,2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol,tripropylene glycol monomethyl ether, dipropylene glycol monoethylglycol, dipropylene glycol monoethyl ether, dipropylene glycolmonomethyl ether, dipropylene glycol, triethylene glycol monomethylether, tetraethylene glycol, triethylene glycol, diethylene glycolmonobutyl ether, diethylene glycol monoethyl ether, diethylene glycolmonomethyl ether, tripropylene glycol, polyethylene glycols havingmolecular weights of 2000 g/mol or lower, 1,3-propylene glycol,isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol,1,5-pentanediol, 1,6-hexanediol, glycerol, erythritol, pentaerythritol,or combinations thereof.

In some examples, the inkjet ink compositions may also containpenetrants for accelerating penetration of the inkjet ink compositioninto the recording medium. Suitable penetrants include polyhydricalcohol alkyl ethers (glycol ethers) and/or 1,2-alkyldiols. Examples ofsuitable polyhydric alcohol alkyl ethers are ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,ethylene glycol monomethyl ether acetate, diethylene glycol monomethylether, diethylene glycol monoethyl ether, ethylene glycol mono-n-propylether, ethylene glycol mono-isopropyl ether, diethylene glycolmono-isopropyl ether, ethylene glycol mono-n-butyl ether, diethyleneglycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether,ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butylether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether,propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether,propylene glycol mono-n-propyl ether, propylene glycol mono-isopropylether, dipropylene glycol monomethyl ether, dipropylene glycol monoethylether, dipropylene glycol mono-n-propyl ether, dipropylene glycolmono-isopropyl ether, propylene glycol mono-n-butyl ether, dipropyleneglycol mono-n-butyl ether, or combinations thereof. Examples of1,2-alkyldiols can include 1,2-pentanediol, 1,2-hexanediol, orcombinations thereof. The penetrant may also be selected fromstraight-chain hydrocarbon diols, such as 1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol,1,8-octanediol, and combinations thereof. Glycerol may also be used as apenetrant.

In some examples, the inkjet ink compositions can contain preservatives.Specific examples of preservatives can include dichlorophene,hexachlorophene, 1,2-benzothiazolin-3-one, 3,4-isothiazolin-3-one, or4,4-dimethyl oxazolidine, alkyl isothiazolone, chloroalkylisothiazolone, benzoisothiazolone, bromonitroalcohol, chloroxylenol, ormixtures thereof.

In some examples, the inkjet ink compositions can include jettabilityadditives. Jettability additives can include LIPONIC® EG-1 (ethoxylatedglycerol; available from Vantage Specialty Ingredients, Inc.).

In some examples, the inkjet ink compositions can include a wax. Waxemulsions are commercially available from a number of vendors, forexample Keim-Additec, Lubrizol, Michelman, and BYK Chemie. Wax emulsionsthat can be useful in this invention include but are not limited to:Lubrizol: LIQUILUBE™ 411, LIQUILUBE™ 405, LIQUILUBE™ 488, LIQUILUBE™443, LIQUILUBE™ 454; Michelman: ME80825, ME48040, ME98040M1, ME61335,ME90842, ME91240, ML160, Keim-Additec: ULTRALUBE® E-521/20, ULTRALUBE®E-7093, ULTRALUBE® 7095/1, ULTRALUBE® E-8046, ULTRALUBE® E-502V,ULTRALUBE® E-842N: Byk: AQUACER® 2650, AQUACER® 507, AQUACER® 533,AQUACER® 515, AQUACER® 537, AQUASLIP™ 671, AQUASLIP™ 942.

The additive(s) can be added singularly or in various combinations tothe inkjet ink compositions described herein in total amounts of fromabout 0.1 wt % to about 10 wt % based on the total weight of the inkjetink composition.

Water

The inkjet ink compositions described herein also include water (e.g.,deionized water) in amounts to make up the balance of the inkjet inkcompositions. In some examples, water can be present in the inkjetcompositions in amounts from about 30 wt % to about 90 wt % based on thetotal weight of the inkjet ink composition. In other examples, theinkjet ink composition can include from about 40 wt % to about 85 wt %water. In further examples, the inkjet ink composition can include fromabout 50 wt % to about 80 wt % water.

Using Polyurethane-Based Binder Dispersion and/or Inkjet Ink(s)

In some examples, a method of using the polyurethane-based binderdispersion described herein is disclosed. This method of using cancomprise adding the polyurethane-based binder dispersion to an inkjetink composition comprising water, at least one colorant, at least oneco-solvent, and at least one surfactant. In some examples, the method ofusing the polyurethane-based binder dispersion can further optionallycomprise applying the inkjet ink composition containing thepolyurethane-based binder dispersion to a media substrate.

After the ink is prepared, the ink(s) may be used by applying to amedium using any inkjet printer (e.g., thermal or piezoelectric). In anexample, the ink(s) may be applied to a coated offset medium. A coatedoffset medium can be any paper coated to impart better image quality byproviding some degree of surface gloss, smoothness, and reduced inkabsorbency. Examples of commercially available coated offset mediainclude Sterling® Ultra Gloss (NewPage Corp.) and UTOPIA® (AppletonCoated LLC). In other examples, the medium may be coated or uncoatedpaper. The medium may also be a vinyl or plastic material.

In some examples, the media or printing surface can include substratesmade from paper, metal, plastic, fabric, or combinations thereof. Insome examples, the media or printing surface can include plain papers,microporous photopapers, coated papers, glossy photopapers, semi-glossphotopapers, heavy weight matte papers, billboard papers, digital fineart papers, calendared papers, vinyl papers, or combinations thereof.

The inkjet ink may be paired with a pre-treatment fixing fluid in aninkjet ink set. In some instances, a pre-treatment fixing fluid may beapplied to the medium prior to printing the inkjet ink onto the medium.The pre-treatment fixing fluid is described in greater detail below.

The pre-treatment fixing fluid may be suitable for wet-on-wet printingon the coated offset media. The pre-treatment fixing fluid includes aparticular combination of salts (at a desirably low content), aparticular co-solvent, and a low HLB (hydrophilic-lipophilic balance)surfactant that is capable of dynamically lowering the surface tensionof the pre-treatment fluid. In the examples disclosed herein, the HLB isless than 10. The selected salt(s), solvent, and surfactant together mayadvantageously promote dot gain and reduce feathering and pigmentflotation, resulting in higher quality text prints. The composition ofthe pre-treatment fixing fluid disclosed herein also exhibits desirablepen reliability.

As mentioned above, the pre-treatment fixing fluid disclosed hereinincludes calcium propionate, calcium pantothenate, tetraethylene glycol,a low HLB surfactant, an acid, and a balance of water. In some examples,the pre-treatment fixing fluid consists of these components alone, andin other examples, the pre-treatment fixing fluid includes thesecomponents and an antimicrobial agent.

The combination of calcium propionate and calcium pantothenate providesthe pre-treatment fixing fluid with metal salts that may cause thepigment or colorant in the ink deposited thereon to coagulate, and thatmay control pigment migration/flotation. The calcium propionate may bepresent in an amount ranging from greater than 4.5 wt % to about 8.0 wt% based on the total weight of the pre-treatment fluid. The calciumpantothenate may be present in an amount ranging from about 2.0 wt % to15 wt % or less. In an example, the pre-treatment fixing fluid mayinclude about 6.5 wt % of calcium propionate and about 4.8 wt % ofcalcium pantothenate. The amount of the metal salts is believed to behigh enough to achieve the desired fixing effect without deleteriouslyaffecting pen reliability.

The pre-treatment fixing fluid also includes tetraethylene glycol as aco-solvent. The tetraethylene glycol may be present in total in thepre-treatment fixing fluid in a range from about 0.1 wt % to about 30 wt%. The amount used may depend, at least in part, on the jettingarchitecture used to apply the pre-treatment fixing fluid. In anexample, the amount of tetraethylene glycol used can be about 12 wt %.

The pre-treatment fixing fluid also includes the low HLB surfactant.This type of surfactant is capable of dynamically controlling, inparticular, lowering, the surface tension of the pre-treatment fixingfluid. The low HLB surfactant may provide the pre-treatment fluid, atthe time of its application, with a surface tension that is lower thanthe surface energy of the coated offset medium upon which thepre-treatment fixing fluid is being applied. As such, the contact anglebetween the pre-treatment fixing fluid and the medium is zero (0), whichenables the pre-treatment fixing fluid to spread out across the mediumsurface in a horizontal direction (with respect to the medium surface),and effectively wet and reduce the surface energy of the offset coatedmedium.

Examples of the low HLB surfactant are a self-emulsifiable wetting agentbased on acetylenic diol chemistry (e.g., SURFYNOL® SE-F) or a nonionic,alkylphenylethoxylate and solvent free surfactant (e.g., CARBOWET®GA-211 surfactant, a.k.a. SURFYNOL® CT-211, from Air Products andChemicals, Inc.). The low HLB surfactant can be present in thepre-treatment fixing fluid in an amount ranging from about 0.01 wt % toabout 1.0 wt % based on the total weight of the pre-treatment fixingfluid. In an example, the amount of the surfactant can be about 0.05 wt%. It is believed that the desired surface tension may not be obtainablewith other amounts and/or other surfactants.

In some examples, the pre-treatment fixing fluid may also include anantimicrobial agent. Antimicrobial agent(s), such as biocides andfungicides, may be added to inhibit the growth of harmfulmicroorganisms. Example antimicrobial agents may include the NUOSEPT®(Ashland Inc.), UCARCIDE® or KORDEK® (Dow Chemical Co.), and PROXEL®(Arch Chemicals) series, and combinations thereof. A total amount of theantimicrobial agents in the pre-treatment fixing fluid may range fromabout 0.05 wt % to about 1 wt %. In an example, the pre-treatment fixingfluid includes about 0.1 wt % of a biocide.

The balance of the pre-treatment fixing fluid can be water. In addition,buffer(s) may be used to adjust the pH of the pre-treatment fixing fluidto a particular pH. One example of a buffer is methanesulfonic acid. Insome examples, the buffer may be used in an amount sufficient to bufferthe pH of the pre-treatment fixing fluid so that it ranges from 4.0 to7.0. In an example, the pH of the pre-treatment fixing fluid can beadjusted to about 6.6 using methanesulfonic acid.

As described above, the surface tension of the pre-treatment fixingfluid is lower than the surface energy of the offset coated medium sothat when the pre-treatment fixing fluid is applied on the surface ofthe offset coated medium, the contact angle between the pre-treatmentfixing fluid and the offset coated medium is 0. In an example, thesurface tension of the pre-treatment fixing fluid is below 37 dyne/cm.In another example, the surface tension of the pre-treatment fixingfluid ranges from about 30 dyne/cm to about 33 dyne/cm. In still anotherexample, the surface energy of the coated offset medium ranges fromabout 34 dyne/cm to about 42 dyne/cm, and the surface tension of thepre-treatment fixing fluid is about 33 dyne/cm or lower.

The pre-treatment fixing fluid may be applied onto the medium using anysuitable high speed (e.g., from about 50 fpm to about 1000 fpm) inkjetprinting apparatus, including thermal inkjet printers or web presses,piezoelectric inkjet printers or web presses, continuous inkjet printersor web presses.

In an example, the amount of pre-treatment fixing fluid that is appliedto the medium ranges from about 1 gsm to about 7 gsm.

In the examples disclosed herein, no drying operation is performed afterthe pre-treatment fixing fluid is applied on the medium. Rather, whilethe pre-treatment fixing fluid is wet, the inkjet ink disclosed hereinis deposited on the pre-treatment fixing fluid on the medium. Whenmultiple ink colors are used, it is to be understood that all of theinks are applied while previously deposited layers are still wet. Theink(s) is also formulated to be deposited by the inkjet printing system.

The salts present in the pre-treatment fixing fluid instantaneouslyreact with the colorant present in the ink, causing the pigment to crashout of ink and fixing the pigment on the medium surface. In addition,the applied pre-treatment fixing fluid provides the coated offset mediumwith a reduced surface energy, which causes the deposited ink(s) tospread less than if the surface energy were higher. This contributes tobleed control and dot gain, and thus enhances the print qualityattributes. This benefit is in addition to the benefits obtained fromthe instantaneous fixing of the colorant(s) in the ink by the salts inthe pre-treatment fixing fluid.

Unless otherwise stated, any feature described hereinabove can becombined with any example or any other feature described herein.

In describing and claiming the examples disclosed herein, the singularforms “a,” “an,” and “the” include plural referents unless the contextclearly dictates otherwise.

It is to be understood that concentrations, amounts, and other numericaldata may be expressed or presented herein in range formats. It is to beunderstood that such range formats are used merely for convenience andbrevity and thus should be interpreted flexibly to include not just thenumerical values explicitly recited as the end points of the range, butalso to include all the individual numerical values or sub-rangesencompassed within that range as if each numerical value and sub-rangeis explicitly recited. As an illustration, a numerical range of “about 1wt % to about 5 wt %” should be interpreted to include not just theexplicitly recited values of about 1 wt % to about 5 wt %, but alsoinclude individual values and subranges within the indicated range.Thus, included in this numerical range are individual values such as 2,3.5, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc.This same principle applies to ranges reciting a single numerical value.

Reference throughout the specification to “one example,” “someexamples,” “another example,” “an example,” and so forth, means that aparticular element (e.g., feature, structure, and/or characteristic)described in connection with the example is included in at least oneexample described herein, and may or may not be present in otherexamples. In addition, it is to be understood that the describedelements for any example may be combined in any suitable manner in thevarious examples unless the context clearly dictates otherwise.

Unless otherwise stated, references herein to “wt %” of a component areto the weight of that component as a percentage of the whole compositioncomprising that component. For example, references herein to “wt %” of,for example, a solid material such as polyurethane(s) or colorant(s)dispersed in a liquid composition are to the weight percentage of thosesolids in the composition, and not to the amount of that solid as apercentage of the total non-volatile solids of the composition.

To further illustrate the present disclosure, examples are given herein.It is to be understood that these examples are provided for illustrativepurposes and are not to be construed as limiting the scope of thepresent disclosure.

If a standard test is mentioned herein, unless otherwise stated, theversion of the test to be referred to is the most recent at the time offiling this patent application.

All amounts in the examples below are in wt % unless indicatedotherwise.

EXAMPLES

Ingredients and Abbreviations

-   -   C: comparison.    -   I: invention.    -   M2070: is a copolymer of poly(ethyleneglycol-co-propyleneglycol)        from Hunstman Chemical.    -   BGDA: is bisphenol A glycerolate dimethacrylate.    -   BPAE: bispehnol A ethoxylate (M, 290 g/mol).    -   CXP-2716: is polycarbonate polyol from Covestro.    -   PTMG1K: is poly(tetrahydrofuran) polyol with M_(n)=1000 g/mol.    -   C-1090: is poly(carbonate) polyol with M_(n)=1000 g/mol (from        Kuraray).    -   C-590: is poly(carbonate) polyol with M_(n)=500 g/mol.    -   ETERNACOLL® UH-50: is polycarbonate diol.    -   PLACCEL™ CD205: is polycaprolactone diol.    -   PPG1K: is poly(propyleneglycol) with M_(n)=1000 g/mol.    -   Taurine: is 2-aminoethanesulfonic acid.    -   EPS: is sodium diaminoethylpropylsulfonate (from Raschig).    -   VESTAMIN® A-95: is sodium diaminoethylethylsulfonate (from        Evonik).    -   MMA: is methyl methacrylate.    -   BA: is n-butyl acrylate.    -   EHA: is 2-ethylhexylacrylate.    -   MAA: is methacrylic acid.    -   TBA: is t-butyl acrylate.    -   TBMA: is t-butyl methacrylate.    -   BzMA: is benzyl methacrylate    -   VA: is vinylacetate.    -   CHMA: is cyclohexyl methacrylate.    -   THFM: is tetrahydrofuran methacrylate.    -   EOEOA: is ethoxyethoxyethylacrylate.    -   PPOM-375: is poly(propyleneglycol) methacrylate (M_(w) 375        g/mol).    -   MPEG-480: is poly(ethyleneoxide) methacrylate (M_(w) 480 g/mol).    -   MPEG-350: is poly(ethyleneglycol) methyl ether acrylate (M_(w)        350 g/mol).    -   EOEO: is di(ethyleneglycol) ethyl ether acrylate.    -   TEGMA: is methyl triethylenglycol methacrylate.    -   Oe: is ethylethoxylacrylate.    -   AIBN: is azobisisobutylonitrile.    -   DBTDL: is dibutyl tin dilaurate.    -   AN: is acrylonitrile.    -   IBM: is isobutyl methacrylate.    -   IBA: is isobutyl acrylate.    -   Sty: is styrene.    -   TFMA: is tetra-hydrofurfuryl methacrylate.    -   DMPA: is 2,2-bis(hydroxymethyl)propionic acid.    -   MEHQ: is hydroquinone monomethyl ether.    -   DAA: is 2-(dimethylamino)ethyl acrylate.    -   HDI: is hexamethylene-1,6-diisocyanate.    -   PTMG1K: is polytetramethylene glycol (M_(w) is 1000 g/mol).    -   PPG1K: is polypropylene glycol (M_(w) is 1000 g/mol).    -   PPG725: is polypropylene glycol (M_(w) is 725 g/mol).

Example 1

Various polyols used in the examples below were synthesized in the samemanner. As an example, Polyol-53, was synthesized as follows:

-   -   1. 600 grams of MMA, 120 grams of EHA, 80 grams of        ethoxyethoxyethylacrylate, 40 grams of thioglycerol, 8 grams of        AIBN, and 600 grams of acetone were mixed in a beaker until the        solution became homogeneous.    -   2. The solution was purged with nitrogen for 20 minutes. A        2-liter four neck round bottom flask equipped with a mechanical        stirrer, a condenser and a nitrogen inlet was immersed in a        constant temperature water bath at 75 C.    -   3. The solution containing the monomers (MMA, EHA, and EOEO),        mercaptan (i.e., thioglycerol), and 2-2′-AIBN was pumped into        the reactor (i.e., the flask) for about two hours. The        polymerization continued for about ten more hours after the        addition of the solution.    -   4. A viscous polymer solution was obtained. The number average        molecular weight (M_(n)) of the viscous polymer was 1800 g/mol.        The weight average molecular weight (M_(w)) of the viscous        polymer was calculated to be 2400 g/mol using Gel Permeation        Chromatography. The % solid was 78%.    -   5. Each of the other example polyols was prepared in a similar        manner as described for Polyol-53, using the components and        amounts set forth in Table 2 below.

TABLE 2 Monomers Ratio Polyol-2 MMA/BA 50/51 Polyol-7 MMA/EHA 75/25Polyol-8 MMA/EHA 50/50 Polyol-9 MMA/EHA 90/10 Polyol-10 MMA/EHA/MAA50/40/10 Polyol-12 MMA/EHA 50/50 Polyol-13 Allyl Methacrylate/EHA 70/30Polyol-14 MMA/EHA 75/25 Polyol-14 MMA/EHA 75/25 Polyol-20 MMA/EHA/DAA70/25/5 Polyol-22 IBM/BA 65/35 Polyol-23 CHMA/EHA 80/20 Polyol-24BzMA/EHA 95/5  Polyol-25 MMA/EHA 75/25 Polyol-26 t-BA/BMA 80/20Polyol-30 CHMA/EHA 95/5  Polyol-31 IBA/MMA/BA 20/57/23 Polyol-32IBA/MMA/BA 40/38/22 Polyol-34 BzMA/MMA/BA 20/60/20 Polyol-35 BzMA/MMA/BA40/44/16 Polyol-36 CHMA/MMA/BA 20/57/23 Polyol-37 CHMA/MMA/BA 40/38/22Polyol-38 IBA/MMA/EHA 20/57/23 Polyol-39 Sty/BMA 40/60 Polyol-41TFMA/MMA/BA 10/65/25 Polyol-43 MMA/EHA/PPOM-375 75/15/10 Polyol-45MMA/EHA/MPEG-480 75/20/5  Polyol-45A MMA/EHA/MPEG-350 75/20/5  Polyol-47MMA/Oe 75/25 Polyol-51 MMA/EHA 82/18 Polyol-53 MMA/EHA/EOEO 75/15/10Polyol-76 IBA/MMA/EHA/EOEO 70/9/11/10 Polyol-77 BzMA/IBA/EHA/EOEO40/45/5/10 Polyol-78 CHMA/IBA/EHA/EOEO 60/18/12/10 Polyol-79CHMA/MMA/EHA/EOEO 60/18/12/10

Comparative Example 1

C-PU-6 was synthesized using diaminoalkylsulfonate using the followingsteps.

-   -   1. 40.6 grams PPG (M_(w) is 1000 g/mol), 169.6 grams of        Polyol-53 (TS 70.7 wt %), 11.67 grams of DMPA, and 70 ml of        acetone were mixed in a 2000 ml of 4-neck round bottom flask.        91.3 grams of HMDI and 20 ml of acetone were added to the flask.    -   2. A mechanical stirrer with glass rod and Teflon blade and a        condenser were attached. The flask was immersed in a constant        temperature bath at about 65° C.    -   3. The system was kept under dry nitrogen blanket.    -   4. 12 drops of dibutyltindilaurate (warmed in about 50° C. oven        first) was added to initiate the polymerization.    -   5. Polymerization was continued for about 8 hours at about        65° C. 0.5 grams samples was withdrawn for % NCO titration to        ensure the first stage reaction was complete. Theoretical % NCO        should be 5.07%.    -   6. 150 ml of acetone was added to dilute the prepolymer solution        and the bath temperature was reduced to about 40° C.    -   7. 61.8 grams of VESTAMIN® A-95 solution (50 wt % solid), 10.85        grams of KOH, and 176.2 grams of deionized water were mixed in a        beaker for about 30 seconds and added to the prepolymer solution        at about 40° C. with vigorous stirring over about 1-3 mins. The        temperature was maintained at about 45° C. for about 30 minutes.        The solution turned viscous and semi-transparent.    -   8. 701 grams of deionized water was pumped to the polymer        mixture over about 15-30 minutes at about 45° C.-50° C. and then        for an additional at least about 60 minutes.    -   9. Acetone was removed under vacuum. The final PU dispersion was        filtered through 400 mesh and fiber glass filter paper. The PU        dispersion particle size measured to be about 25.8 nm in radius.        The PU dispersion pH was about 10.3. The PU dispersion % solids        was measured to be about 25.5 wt % and the PU dispersion was        measured to have a viscosity of about 6.4 cps.

Example 2

I-PU-1 was synthesized using diaminoalkylsulfonate using the followingsteps.

-   -   1. 42.6 grams PPG (M_(w) is 1000 g/mol), 186.15 grams of        Polyol-53 (TS 70.7 wt %), 12.24 grams of DMPA, and 70 ml of        acetone were mixed in a 2000 ml of 4-neck round bottom flask.        81.2 grams of IPDI and 20 ml of acetone were added to the flask.    -   2. A mechanical stirrer with glass rod and Teflon blade and a        condenser were attached. The flask was immersed in a constant        temperature bath at about 65° C.    -   3. The system was kept under dry nitrogen blanket.    -   4. 12 drops of dibutyltindilaurate (warmed in about 50° C. oven        first) was added to initiate the polymerization.    -   5. Polymerization was continued for about 8 hours at about        65° C. 0.5 grams samples was withdrawn for % NCO titration to        ensure the first stage reaction was complete. Theoretical % NCO        should be 5.35%.    -   6. 150 ml of acetone was added to dilute the prepolymer solution        and the bath temperature was reduced to about 40° C.    -   7. 64.8 grams of VESTAMIN® A-95 solution (50 wt % solid), and        162.0 grams of deionized water were mixed in a beaker for about        30 seconds and added to the prepolymer solution at about 40° C.        with vigorous stirring over about 1-3 mins. The temperature was        maintained at about 45° C. for about 30 minutes. The solution        turned viscous and semi-transparent.    -   8. 11.38 grams of KOH (45%) and 34.1 grams of water were mixed        in a beaker and added to the mixture above and mixed for another        20 minutes.    -   9. 972 grams of deionized water was pumped to the polymer        mixture over about 15-30 minutes at about 45° C.-50° C. and then        for an additional at least about 60 minutes.    -   10. Acetone was removed under vacuum. The final PU dispersion        was filtered through 400 mesh and fiber glass filter paper. The        PU dispersion particle size measured to be about 25.8 nm in        radius. The PU dispersion pH was about 10.3. The PU dispersion %        solids was measured to be about 23.1 wt % and the PU dispersion        was measured to have a viscosity of about 6.4 cps.

Example 3

Additional polyurethane-based binder dispersions (i.e., PUs) weresynthesized in the same manner as Example 2 using the materials andamounts summarized in Table 3 below.

TABLE 3 Acrylonitrile PU ID (wt %) (A) (B) (C) (D) (E) (F) Wt % C-PU-142.1 IPDI Polyol-14 BGDA DMPA Taurine M2070 21.1/51.3/13.3/1.6/7.9/4.7C-PU-2 45.7 HMDI Polyol-14 C-590 DMPA VESTAMIN ® —32.1/44.1/10.0/4.1/9.7 A-95 C-PU-3 48.1 IPDI Polyol-34 C-590 DMPAVESTAMIN ® — 28.6/46.4/10.5/4.3/10.2 A-95 C-PU-4 48.1 IPDI Polyol-38C-590 DMPA VESTAMIN ® — 28.6/46.4/10.5/4.3/10.2 A-95 C-PU-5 48.1 IPDIPolyol-47 C-590 DMPA VESTAMIN ® — 28.6/46.4/10.5/4.3/10.2 A-95 C-PU-646.7 HMDI Polyol-53 PPG1K DMPA VESTAMIN ® — 30.4/41.8/13.5/3.9/10.3 A-95C-PU-7 48.1 IPDI Polyol-14 C-590 DMPA VESTAMIN ® —28.6/46.4/10.5/4.3/10.2 A-95 C-PU-8 48.1 IPDI Polyol-37 C-590 DMPAVESTAMIN ® — 28.6/46.4/10.5/4.3/10.2 A-95 C-PU-9 44.7 IPDI Polyol-14C-590 DMPA VESTAMIN ® M2070 27.2/44.2/10/4.1/9.3/5.1 A-95 C-PU-10 48.1IPDI Polyol-45 C-590 DMPA VESTAMIN ® — 28.6/46.4/10.5/4.3/10.2 A-95C-PU-11 48.1 IPDI Polyol-43 C-590 DMPA VESTAMIN ® —28.6/46.4/10.5/4.3/10.2 A-95 I-PU-1 48.9 IPDI Polyol-53 PPG1K DMPAVESTAMIN ® — 27/43.9/14.2/4.1/10.8 A-95 I-PU-2 56.4 IPDI Polyol-45APPG1K DMPA VESTAMIN ® — 29.8/36.2/16.7/4.5/12.7 A-95 I-PU-3 56.4 IPDIPolyol-14 PPG1K DMPA VESTAMIN ® — 29.8/36.2/16.7/4.5/12.7 A-95 I-PU-458.5 IPDI Polyol-14 PTMG1K DMPA VESTAMIN ® — 27.2/48.6/12.3/4.1/7.8/4.1A-95/Taurine I-PU-5 48.9 IPDI Polyol-51 PPG1K DMPA VESTAMIN ® —27/43.9/14.2/4.1/10.8 A-95 I-PU-6 47.8 IPDI Polyol-14 PPG1K DMPAVESTAMIN ® — 26.7/43.3/15/3.4/11/4 A-95 I-PU-7 50.2 IPDI Polyol-53PPG725 DMPA VESTAMIN ® — 28/45.5/11.4/4.9/10 A-95

Prophetic Example 1

Additional polyurethane-based binder dispersions (i.e., PUs) can besynthesized in the same manner as Example 2 using sulfonic/sulfonateamine compounds having three to ten amino groups.

Example 4

Sustained Printing and Recovery (SPAR) was tested for some PUdispersions summarized in Table 3 above. SPAR testing involvedcontinuous printing of a pre-determined stress image into a wastecontainer for a defined period of time. After this, a servicingalgorithm was applied to recover degraded nozzle health and to cleanresidual ink (from puddling or aerosol) on the nozzle plate. In betweenthe stress image print cycles, a nozzle health pattern was printed, totrack the nozzle health performance over time.

The nozzle health pattern was graded using the Inspector nozzle healthalgorithm—the metrics used include missing nozzles, vertical trajectoryerror or deviated nozzles (greater than 30 μm relative to the averagemeasured nozzle-to-nozzle vertical spacing) and weak nozzles. Thesemetrics are used to determine what kind of obstruction is at the nozzle.Thresholds (given a B grade, i.e., greater than or equal to 40 defectivenozzles) and targets (given an A grade, i.e., greater than or equal to10 defective nozzles but less than 40 defective nozzles) for nozzlehealth performance is defined by summing all three metrics above per pentrench. The threshold and target were based on studies on the impact ofmissing nozzles to IQ.

FIG. 1 shows a bar graph of polyurethane dispersions versus the averageof the sum of defective nozzles. This FIG. 1 shows that C-PU-7 failedthe sustained printing test because its average number of the sum of alldefective nozzles was well over target “A” and threshold “B.” Incontrast, I-PU-3 and I-PU-1 show much better performance, having averagenumbers of the sum of defective nozzles that were under the target “A”and threshold “B.” The higher the defective number of nozzles, the worsethe PU dispersion performed (higher number=more defective nozzles=worsesustained printing performance). The sum of defective number of nozzlesincludes an average across multiple sustained printing tests andmultiple ink colors (i.e., black and magenta).

Example 5

Inkjet ink compositions A-D were prepared as summarized in Table 4 belowusing various polyurethane-based binder dispersions (PU-X; identified indetail in Table 5) from Table 3 above.

TABLE 4 Ink Ink Ink Ink Compo- Compo- Compo- Compo- sition sition sitionsition A (wt %) B (wt %) C (wt %) D (wt %) 1-(2-Hydroxyethyl)-2- 5.00 —5.00 — pyrrolidone Glycerol — 6.00 — 6.00 Tripropylene glycol — 3.00 —3.00 methyl ether (DOWANOL ™ TPM) CRODAFOS ™ N3 0.50 0.50 0.50 0.50SURFYNOL ® SE-F 0.30 — 0.30 — SURFYNOL ® CT-211 0.30 — 0.30 — SURFYNOL ®440 — 0.25 — 0.25 DYNOL ™ 360 — 0.25 — 0.25 LIPONIC ® EG-1 1.00 2.001.00 2.00 LIQUILUBE ™ 1.00 0.75 1.00 0.75 405 Wax Polyurethane 5.00 5.003.50 3.50 Binder (PU-X) Styrene acrylate 2.75 2.75 — — with blackpigment Styrene acrylate — — 4.00 4.00 with magenta pigment Water 84.15 79.50  84.40  79.75  Total 100    100    100    100   

The SPAR performance of PU dispersions in Table 3 is summarized in Table5 below. The SPAR test score is the combination of jetting performanceand ease of servicing. 5 is the best and 1 is the worst in SPAR testscores.

TABLE 5 Component Component Ink PU ID (A) (C) SPAR Composition C-PU-2HMDI C-590 1 A, C C-PU-3 IPDI C-590 1 A, C C-PU-4 IPDI C-590 1 A, CC-PU-5 IPDI C-590 1 A, C C-PU-6 HMDI PPG1K 1 B, D C-PU-7 IPDI C-590 2 A,C C-PU-8 IPDI C-590 2 A, C C-PU-9 IPDI C-590 2 A, C C-PU-10 IPDI C-590 2A, C C-PU-11 IPDI C-590 2 A, C I-PU-1 IPDI PPG1K 4.5 A, C I-PU-2 IPDIPPG1K 4 A, B, C, D I-PU-3 IPDI PPG1K 4.5 A, C I-PU-4 IPDI PTMG1K 4 A, B,C, D I-PU-5 IPDI PPG1K 4 A, C I-PU-6 IPDI PPG1K 4 B, D I-PU-7 IPDIPPG725 4 B, D

As shown in Table 5 above, the PU dispersions with the combination ofIPDI with PPG or PTMG (polyether polyol) demonstrated much better SPARresults than with the combination of HMDI with PPG or the combination ofIPDI with C-590 (polycarbonate polyol).

The polyurethane-based binder dispersions described above exhibit greatSPAR performance over many hours of printing and as a result requirelittle or no printhead servicing while printing. This enables higherprint speeds and therefore higher press productivity for packaging pressowners. The ability to recover the printheads with minimal servicingreduces down time and increases press productivity which can beimportant in the industrial printing market.

In addition, the above-described polyurethane-based binder dispersionscan still be used in high amounts in the ink compositions (e.g., 3.5 wt% or 5 wt %), enabling prints with durability.

While several examples have been described in detail, it is to beunderstood that the disclosed examples may be modified. Therefore, theforegoing description is to be considered non-limiting.

What is claimed is:
 1. An inkjet ink composition, comprising: water; atleast one co-solvent; at least one surfactant; at least one colorant;and a polyurethane-based binder dispersion comprising: water and apolyurethane, wherein the polyurethane comprises: (A) a polyisocyanate,which is isophorone diisocyanate (IPDI),2,2,4-trimethyl-hexamethylene-diisocyanate (TMDI),dicyclohexylmethane-4,4-diisocyanate (H12MDI),hexamethylene-1,6-diisocyanate(HDI), or mixtures thereof, (B) a firstpolyol having a chain with two hydroxyl functional groups at one end ofthe chain and no hydroxyl groups at an opposed end of the chain, (C) asecond polyol having a chain with one hydroxyl functional group at eachend of the chain, (D) a hydroxyl-carboxylic acid having a formula:(HO)_(x)Q(COOH)_(y), where Q is a straight or branched hydrocarbonradical containing 1 to 12 carbon atoms, and x is 2 or 3 and y rangesfrom 1 to 3, (E) a sulfonate or sulfonic acid amine compound having twoamino functional groups, and (F) an optional homopolymer or copolymer ofpoly(ethylene glycol) having one or two hydroxyl functional groups orone or two amino functional groups at one end of its chain.
 2. Theinkjet ink composition of claim 1, wherein (A) is present in thepolyurethane-based binder dispersion in an amount of from about 20 wt %to about 35 wt % based on the total weight of the polyurethane-basedbinder dispersion.
 3. The inkjet ink composition of claim 1, wherein (B)is present in the polyurethane-based binder dispersion in an amount offrom about 30 wt % to about 60 wt % based on the total weight of thepolyurethane-based binder dispersion.
 4. The inkjet ink composition ofclaim 1, wherein: (B) is formed from a free radical polymerization of amonomer in the presence of a mercaptan including two hydroxyl functionalgroups or two carboxylic functional groups; the monomer is selected fromthe group consisting of an alkylester of acrylic acid, an alkylester ofmethacrylic acid, an acid group containing monomer, acrylamide, anacrylamide derivative, methacrylamide, a methacrylamide derivative,styrene, a styrene derivative, acrylonitrile, vinylidene chloride, afluorine containing acrylate, a fluorine containing methacrylate, asiloxane containing acrylate, a siloxane containing methacrylate, vinylacetate, N-vinylpyrrolidone, and combinations thereof; and the mercaptanis selected from the group consisting of 1,2-propanediol (thioglycerol),1-mercapto-1,1-ethanediol, 2-mercapto-1,3-propanediol,2-mercapto-2-methyl-1,3-propanediol, 2-mercapto-2-ethyl-1,3-propanediol,1-mercapto-2,3-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol,and thioglycolic acid.
 5. The inkjet ink composition of claim 1, wherein(C) is present in the polyurethane-based binder dispersion in an amountof from about 8 wt % to about 20 wt % based on the total weight of thepolyurethane-based binder dispersion.
 6. The inkjet ink composition ofclaim 1, wherein (C) is poly(propyleneglycol), poly(tetrahydrofuran),poly(carbonate) polyol, or mixtures thereof.
 7. The inkjet inkcomposition of claim 1, wherein (D) is present in the polyurethane-basedbinder dispersion in an amount of from about 2 wt % to about 8 wt %based on the total weight of the polyurethane-based binder dispersion.8. The inkjet ink composition of claim 1, wherein (D) isdimethylolpropionic acid (DMPA), dimethylol butanoic acid (DMBA),tartaric acid, dihydroxymaleic acid; or mixtures thereof.
 9. The inkjetink composition of claim 1, wherein (E) is present in thepolyurethane-based binder dispersion in an amount of from about 5 wt %to about 15 wt % based on the total weight of the polyurethane-basedbinder dispersion.
 10. The inkjet ink composition of claim 1, wherein(E) is ethyldiamineethylsulfonic acid or a salt thereof,ethyldiaminepropylsulfonic acid or a salt thereof,5-amino-2-(aminomethyl)-1-pentanesulfonic acid or a salt thereof,2,3-diamino-1-propanesulfonic acid or a salt thereof,3-[bis(2-aminoethyl)amino]-1-propanesulfonic acid or a salt thereof,2-[bis(2-aminoethyl)amino]-ethanesulfonic acid or a salt thereof,2-[(2-aminoethyl)amino]-1-propanesulfonic acid or a salt thereof,2-[[2-[(1-methylethyl)amino]ethyl]amino]-ethanesulfonic acid or a saltthereof, 2-[(2-aminoethyl)amino]-1-pentanesulfonic acid or a saltthereof, or mixtures thereof.
 11. The inkjet ink composition of claim 1,wherein (A) is isophorone diisocyanate, which is present in thepolyurethane in an amount of from about 24 wt % to about 30 wt % basedon the total weight of the polyurethane, (B) is a copolymer of methylmethacrylate-co-ethylhexylacrylate-co-ethoxyethoxyethylacrylate with thetwo hydroxyl functional groups at the one end, which is present in thepolyurethane in an amount of from about 40 wt % to about 50 wt % basedon the total weight of the polyurethane, wherein (B) the copolymercomprises about 75 wt % of methyl methacrylate, about 15 wt % ofethylhexylacrylate, and about 10 wt % of ethoxyethoxyethylacrylate, eachbased on the total weight of (B), (C) is polypropylene glycol with a Mnof 1000 g/mol, which is present in the polyurethane in an amount of fromabout 12 wt % to about 18 wt % based on the total weight of thepolyurethane, (D) is dimethylolpropionic acid, which is present in thepolyurethane in an amount of from about 2 wt % to about 6 wt % based onthe total weight of the polyurethane, and (E) is sodium2-[(2-aminoethyl)amino]ethanesulphonate, which is present in thepolyurethane in an amount of from about 8 wt % to about 12 wt % based onthe total weight of the polyurethane.
 12. A method of making the inkjetink composition of claim 1 comprising: mixing the water; the at leastone co-solvent; the at least one surfactant; the at least one colorant;and the polyurethane-based binder dispersion.